Merging upstream version 1.72.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 0 insertions, 792 deletions

diff --git a/compiler/rustc_traits/src/chalk/db.rs b/compiler/rustc_traits/src/chalk/db.rs
deleted file mode 100644
index c319b2e31..000000000
--- a/compiler/rustc_traits/src/chalk/db.rs
+++ /dev/null
@@ -1,792 +0,0 @@
-//! Provides the `RustIrDatabase` implementation for `chalk-solve`
-//!
-//! The purpose of the `chalk_solve::RustIrDatabase` is to get data about
-//! specific types, such as bounds, where clauses, or fields. This file contains
-//! the minimal logic to assemble the types for `chalk-solve` by calling out to
-//! either the `TyCtxt` (for information about types) or
-//! `crate::chalk::lowering` (to lower rustc types into Chalk types).
-
-use rustc_middle::traits::ChalkRustInterner as RustInterner;
-use rustc_middle::ty::{self, AssocKind, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable};
-use rustc_middle::ty::{InternalSubsts, SubstsRef};
-use rustc_target::abi::{Integer, IntegerType};
-
-use rustc_ast::ast;
-
-use rustc_hir::def_id::DefId;
-
-use rustc_span::symbol::sym;
-
-use std::fmt;
-use std::sync::Arc;
-
-use crate::chalk::lowering::LowerInto;
-
-pub struct RustIrDatabase<'tcx> {
-    pub(crate) interner: RustInterner<'tcx>,
-}
-
-impl fmt::Debug for RustIrDatabase<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "RustIrDatabase")
-    }
-}
-
-impl<'tcx> RustIrDatabase<'tcx> {
-    fn where_clauses_for(
-        &self,
-        def_id: DefId,
-        bound_vars: SubstsRef<'tcx>,
-    ) -> Vec<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>> {
-        self.interner
-            .tcx
-            .predicates_defined_on(def_id)
-            .instantiate_own(self.interner.tcx, bound_vars)
-            .filter_map(|(wc, _)| LowerInto::lower_into(wc, self.interner))
-            .collect()
-    }
-
-    fn bounds_for<T>(&self, def_id: DefId, bound_vars: SubstsRef<'tcx>) -> Vec<T>
-    where
-        ty::Predicate<'tcx>: LowerInto<'tcx, std::option::Option<T>>,
-    {
-        self.interner
-            .tcx
-            .explicit_item_bounds(def_id)
-            .subst_iter_copied(self.interner.tcx, &bound_vars)
-            .filter_map(|(bound, _)| LowerInto::<Option<_>>::lower_into(bound, self.interner))
-            .collect()
-    }
-}
-
-impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'tcx> {
-    fn interner(&self) -> RustInterner<'tcx> {
-        self.interner
-    }
-
-    fn associated_ty_data(
-        &self,
-        assoc_type_id: chalk_ir::AssocTypeId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::AssociatedTyDatum<RustInterner<'tcx>>> {
-        let def_id = assoc_type_id.0;
-        let assoc_item = self.interner.tcx.associated_item(def_id);
-        let Some(trait_def_id) = assoc_item.trait_container(self.interner.tcx) else {
-            unimplemented!("Not possible??");
-        };
-        match assoc_item.kind {
-            AssocKind::Type => {}
-            _ => unimplemented!("Not possible??"),
-        }
-        let bound_vars = bound_vars_for_item(self.interner.tcx, def_id);
-        let binders = binders_for(self.interner, bound_vars);
-
-        let where_clauses = self.where_clauses_for(def_id, bound_vars);
-        let bounds = self.bounds_for(def_id, bound_vars);
-
-        Arc::new(chalk_solve::rust_ir::AssociatedTyDatum {
-            trait_id: chalk_ir::TraitId(trait_def_id),
-            id: assoc_type_id,
-            name: (),
-            binders: chalk_ir::Binders::new(
-                binders,
-                chalk_solve::rust_ir::AssociatedTyDatumBound { bounds, where_clauses },
-            ),
-        })
-    }
-
-    fn trait_datum(
-        &self,
-        trait_id: chalk_ir::TraitId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::TraitDatum<RustInterner<'tcx>>> {
-        use chalk_solve::rust_ir::WellKnownTrait::*;
-
-        let def_id = trait_id.0;
-        let trait_def = self.interner.tcx.trait_def(def_id);
-
-        let bound_vars = bound_vars_for_item(self.interner.tcx, def_id);
-        let binders = binders_for(self.interner, bound_vars);
-
-        let where_clauses = self.where_clauses_for(def_id, bound_vars);
-
-        let associated_ty_ids: Vec<_> = self
-            .interner
-            .tcx
-            .associated_items(def_id)
-            .in_definition_order()
-            .filter(|i| i.kind == AssocKind::Type)
-            .map(|i| chalk_ir::AssocTypeId(i.def_id))
-            .collect();
-
-        let lang_items = self.interner.tcx.lang_items();
-        let well_known = if lang_items.sized_trait() == Some(def_id) {
-            Some(Sized)
-        } else if lang_items.copy_trait() == Some(def_id) {
-            Some(Copy)
-        } else if lang_items.clone_trait() == Some(def_id) {
-            Some(Clone)
-        } else if lang_items.drop_trait() == Some(def_id) {
-            Some(Drop)
-        } else if lang_items.fn_trait() == Some(def_id) {
-            Some(Fn)
-        } else if lang_items.fn_once_trait() == Some(def_id) {
-            Some(FnOnce)
-        } else if lang_items.fn_mut_trait() == Some(def_id) {
-            Some(FnMut)
-        } else if lang_items.unsize_trait() == Some(def_id) {
-            Some(Unsize)
-        } else if lang_items.unpin_trait() == Some(def_id) {
-            Some(Unpin)
-        } else if lang_items.coerce_unsized_trait() == Some(def_id) {
-            Some(CoerceUnsized)
-        } else if lang_items.dispatch_from_dyn_trait() == Some(def_id) {
-            Some(DispatchFromDyn)
-        } else if lang_items.tuple_trait() == Some(def_id) {
-            Some(Tuple)
-        } else {
-            None
-        };
-        Arc::new(chalk_solve::rust_ir::TraitDatum {
-            id: trait_id,
-            binders: chalk_ir::Binders::new(
-                binders,
-                chalk_solve::rust_ir::TraitDatumBound { where_clauses },
-            ),
-            flags: chalk_solve::rust_ir::TraitFlags {
-                auto: trait_def.has_auto_impl,
-                marker: trait_def.is_marker,
-                upstream: !def_id.is_local(),
-                fundamental: self.interner.tcx.has_attr(def_id, sym::fundamental),
-                non_enumerable: true,
-                coinductive: false,
-            },
-            associated_ty_ids,
-            well_known,
-        })
-    }
-
-    fn adt_datum(
-        &self,
-        adt_id: chalk_ir::AdtId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::AdtDatum<RustInterner<'tcx>>> {
-        let adt_def = adt_id.0;
-
-        let bound_vars = bound_vars_for_item(self.interner.tcx, adt_def.did());
-        let binders = binders_for(self.interner, bound_vars);
-
-        let where_clauses = self.where_clauses_for(adt_def.did(), bound_vars);
-
-        let variants: Vec<_> = adt_def
-            .variants()
-            .iter()
-            .map(|variant| chalk_solve::rust_ir::AdtVariantDatum {
-                fields: variant
-                    .fields
-                    .iter()
-                    .map(|field| field.ty(self.interner.tcx, bound_vars).lower_into(self.interner))
-                    .collect(),
-            })
-            .collect();
-        Arc::new(chalk_solve::rust_ir::AdtDatum {
-            id: adt_id,
-            binders: chalk_ir::Binders::new(
-                binders,
-                chalk_solve::rust_ir::AdtDatumBound { variants, where_clauses },
-            ),
-            flags: chalk_solve::rust_ir::AdtFlags {
-                upstream: !adt_def.did().is_local(),
-                fundamental: adt_def.is_fundamental(),
-                phantom_data: adt_def.is_phantom_data(),
-            },
-            kind: match adt_def.adt_kind() {
-                ty::AdtKind::Struct => chalk_solve::rust_ir::AdtKind::Struct,
-                ty::AdtKind::Union => chalk_solve::rust_ir::AdtKind::Union,
-                ty::AdtKind::Enum => chalk_solve::rust_ir::AdtKind::Enum,
-            },
-        })
-    }
-
-    fn adt_repr(
-        &self,
-        adt_id: chalk_ir::AdtId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::AdtRepr<RustInterner<'tcx>>> {
-        let adt_def = adt_id.0;
-        let int = |i| chalk_ir::TyKind::Scalar(chalk_ir::Scalar::Int(i)).intern(self.interner);
-        let uint = |i| chalk_ir::TyKind::Scalar(chalk_ir::Scalar::Uint(i)).intern(self.interner);
-        Arc::new(chalk_solve::rust_ir::AdtRepr {
-            c: adt_def.repr().c(),
-            packed: adt_def.repr().packed(),
-            int: adt_def.repr().int.map(|i| match i {
-                IntegerType::Pointer(true) => int(chalk_ir::IntTy::Isize),
-                IntegerType::Pointer(false) => uint(chalk_ir::UintTy::Usize),
-                IntegerType::Fixed(i, true) => match i {
-                    Integer::I8 => int(chalk_ir::IntTy::I8),
-                    Integer::I16 => int(chalk_ir::IntTy::I16),
-                    Integer::I32 => int(chalk_ir::IntTy::I32),
-                    Integer::I64 => int(chalk_ir::IntTy::I64),
-                    Integer::I128 => int(chalk_ir::IntTy::I128),
-                },
-                IntegerType::Fixed(i, false) => match i {
-                    Integer::I8 => uint(chalk_ir::UintTy::U8),
-                    Integer::I16 => uint(chalk_ir::UintTy::U16),
-                    Integer::I32 => uint(chalk_ir::UintTy::U32),
-                    Integer::I64 => uint(chalk_ir::UintTy::U64),
-                    Integer::I128 => uint(chalk_ir::UintTy::U128),
-                },
-            }),
-        })
-    }
-
-    fn adt_size_align(
-        &self,
-        adt_id: chalk_ir::AdtId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::AdtSizeAlign> {
-        let tcx = self.interner.tcx;
-        let did = adt_id.0.did();
-
-        // Grab the ADT and the param we might need to calculate its layout
-        let param_env = tcx.param_env(did);
-        let adt_ty = tcx.type_of(did).subst_identity();
-
-        // The ADT is a 1-zst if it's a ZST and its alignment is 1.
-        // Mark the ADT as _not_ a 1-zst if there was a layout error.
-        let one_zst = if let Ok(layout) = tcx.layout_of(param_env.and(adt_ty)) {
-            layout.is_zst() && layout.align.abi.bytes() == 1
-        } else {
-            false
-        };
-
-        Arc::new(chalk_solve::rust_ir::AdtSizeAlign::from_one_zst(one_zst))
-    }
-
-    fn fn_def_datum(
-        &self,
-        fn_def_id: chalk_ir::FnDefId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::FnDefDatum<RustInterner<'tcx>>> {
-        let def_id = fn_def_id.0;
-        let bound_vars = bound_vars_for_item(self.interner.tcx, def_id);
-        let binders = binders_for(self.interner, bound_vars);
-
-        let where_clauses = self.where_clauses_for(def_id, bound_vars);
-
-        let sig = self.interner.tcx.fn_sig(def_id);
-        let (inputs_and_output, iobinders, _) = crate::chalk::lowering::collect_bound_vars(
-            self.interner,
-            self.interner.tcx,
-            sig.map_bound(|s| s.inputs_and_output()).subst(self.interner.tcx, bound_vars),
-        );
-
-        let argument_types = inputs_and_output[..inputs_and_output.len() - 1]
-            .iter()
-            .map(|t| sig.rebind(*t).subst(self.interner.tcx, &bound_vars).lower_into(self.interner))
-            .collect();
-
-        let return_type = sig
-            .rebind(inputs_and_output[inputs_and_output.len() - 1])
-            .subst(self.interner.tcx, &bound_vars)
-            .lower_into(self.interner);
-
-        let bound = chalk_solve::rust_ir::FnDefDatumBound {
-            inputs_and_output: chalk_ir::Binders::new(
-                iobinders,
-                chalk_solve::rust_ir::FnDefInputsAndOutputDatum { argument_types, return_type },
-            ),
-            where_clauses,
-        };
-        Arc::new(chalk_solve::rust_ir::FnDefDatum {
-            id: fn_def_id,
-            sig: sig.0.lower_into(self.interner),
-            binders: chalk_ir::Binders::new(binders, bound),
-        })
-    }
-
-    fn impl_datum(
-        &self,
-        impl_id: chalk_ir::ImplId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::ImplDatum<RustInterner<'tcx>>> {
-        let def_id = impl_id.0;
-        let bound_vars = bound_vars_for_item(self.interner.tcx, def_id);
-        let binders = binders_for(self.interner, bound_vars);
-
-        let trait_ref = self.interner.tcx.impl_trait_ref(def_id).expect("not an impl");
-        let trait_ref = trait_ref.subst(self.interner.tcx, bound_vars);
-
-        let where_clauses = self.where_clauses_for(def_id, bound_vars);
-
-        let value = chalk_solve::rust_ir::ImplDatumBound {
-            trait_ref: trait_ref.lower_into(self.interner),
-            where_clauses,
-        };
-
-        let associated_ty_value_ids: Vec<_> = self
-            .interner
-            .tcx
-            .associated_items(def_id)
-            .in_definition_order()
-            .filter(|i| i.kind == AssocKind::Type)
-            .map(|i| chalk_solve::rust_ir::AssociatedTyValueId(i.def_id))
-            .collect();
-
-        Arc::new(chalk_solve::rust_ir::ImplDatum {
-            polarity: self.interner.tcx.impl_polarity(def_id).lower_into(self.interner),
-            binders: chalk_ir::Binders::new(binders, value),
-            impl_type: chalk_solve::rust_ir::ImplType::Local,
-            associated_ty_value_ids,
-        })
-    }
-
-    fn impls_for_trait(
-        &self,
-        trait_id: chalk_ir::TraitId<RustInterner<'tcx>>,
-        parameters: &[chalk_ir::GenericArg<RustInterner<'tcx>>],
-        _binders: &chalk_ir::CanonicalVarKinds<RustInterner<'tcx>>,
-    ) -> Vec<chalk_ir::ImplId<RustInterner<'tcx>>> {
-        let def_id = trait_id.0;
-
-        // FIXME(chalk): use TraitDef::for_each_relevant_impl, but that will
-        // require us to be able to interconvert `Ty<'tcx>`, and we're
-        // not there yet.
-
-        let all_impls = self.interner.tcx.all_impls(def_id);
-        let matched_impls = all_impls.filter(|impl_def_id| {
-            use chalk_ir::could_match::CouldMatch;
-            let trait_ref = self.interner.tcx.impl_trait_ref(*impl_def_id).unwrap();
-            let bound_vars = bound_vars_for_item(self.interner.tcx, *impl_def_id);
-
-            let self_ty = trait_ref.map_bound(|t| t.self_ty());
-            let self_ty = self_ty.subst(self.interner.tcx, bound_vars);
-            let lowered_ty = self_ty.lower_into(self.interner);
-
-            parameters[0].assert_ty_ref(self.interner).could_match(
-                self.interner,
-                self.unification_database(),
-                &lowered_ty,
-            )
-        });
-
-        let impls = matched_impls.map(chalk_ir::ImplId).collect();
-        impls
-    }
-
-    fn impl_provided_for(
-        &self,
-        auto_trait_id: chalk_ir::TraitId<RustInterner<'tcx>>,
-        chalk_ty: &chalk_ir::TyKind<RustInterner<'tcx>>,
-    ) -> bool {
-        use chalk_ir::Scalar::*;
-        use chalk_ir::TyKind::*;
-
-        let trait_def_id = auto_trait_id.0;
-        let all_impls = self.interner.tcx.all_impls(trait_def_id);
-        for impl_def_id in all_impls {
-            let trait_ref = self.interner.tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
-            let self_ty = trait_ref.self_ty();
-            let provides = match (self_ty.kind(), chalk_ty) {
-                (&ty::Adt(impl_adt_def, ..), Adt(id, ..)) => impl_adt_def.did() == id.0.did(),
-                (_, AssociatedType(_ty_id, ..)) => {
-                    // FIXME(chalk): See https://github.com/rust-lang/rust/pull/77152#discussion_r494484774
-                    false
-                }
-                (ty::Bool, Scalar(Bool)) => true,
-                (ty::Char, Scalar(Char)) => true,
-                (ty::Int(ty1), Scalar(Int(ty2))) => matches!(
-                    (ty1, ty2),
-                    (ty::IntTy::Isize, chalk_ir::IntTy::Isize)
-                        | (ty::IntTy::I8, chalk_ir::IntTy::I8)
-                        | (ty::IntTy::I16, chalk_ir::IntTy::I16)
-                        | (ty::IntTy::I32, chalk_ir::IntTy::I32)
-                        | (ty::IntTy::I64, chalk_ir::IntTy::I64)
-                        | (ty::IntTy::I128, chalk_ir::IntTy::I128)
-                ),
-                (ty::Uint(ty1), Scalar(Uint(ty2))) => matches!(
-                    (ty1, ty2),
-                    (ty::UintTy::Usize, chalk_ir::UintTy::Usize)
-                        | (ty::UintTy::U8, chalk_ir::UintTy::U8)
-                        | (ty::UintTy::U16, chalk_ir::UintTy::U16)
-                        | (ty::UintTy::U32, chalk_ir::UintTy::U32)
-                        | (ty::UintTy::U64, chalk_ir::UintTy::U64)
-                        | (ty::UintTy::U128, chalk_ir::UintTy::U128)
-                ),
-                (ty::Float(ty1), Scalar(Float(ty2))) => matches!(
-                    (ty1, ty2),
-                    (ty::FloatTy::F32, chalk_ir::FloatTy::F32)
-                        | (ty::FloatTy::F64, chalk_ir::FloatTy::F64)
-                ),
-                (&ty::Tuple(substs), Tuple(len, _)) => substs.len() == *len,
-                (&ty::Array(..), Array(..)) => true,
-                (&ty::Slice(..), Slice(..)) => true,
-                (&ty::RawPtr(type_and_mut), Raw(mutability, _)) => {
-                    match (type_and_mut.mutbl, mutability) {
-                        (ast::Mutability::Mut, chalk_ir::Mutability::Mut) => true,
-                        (ast::Mutability::Mut, chalk_ir::Mutability::Not) => false,
-                        (ast::Mutability::Not, chalk_ir::Mutability::Mut) => false,
-                        (ast::Mutability::Not, chalk_ir::Mutability::Not) => true,
-                    }
-                }
-                (&ty::Ref(.., mutability1), Ref(mutability2, ..)) => {
-                    match (mutability1, mutability2) {
-                        (ast::Mutability::Mut, chalk_ir::Mutability::Mut) => true,
-                        (ast::Mutability::Mut, chalk_ir::Mutability::Not) => false,
-                        (ast::Mutability::Not, chalk_ir::Mutability::Mut) => false,
-                        (ast::Mutability::Not, chalk_ir::Mutability::Not) => true,
-                    }
-                }
-                (
-                    &ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }),
-                    OpaqueType(opaque_ty_id, ..),
-                ) => def_id == opaque_ty_id.0,
-                (&ty::FnDef(def_id, ..), FnDef(fn_def_id, ..)) => def_id == fn_def_id.0,
-                (&ty::Str, Str) => true,
-                (&ty::Never, Never) => true,
-                (&ty::Closure(def_id, ..), Closure(closure_id, _)) => def_id == closure_id.0,
-                (&ty::Foreign(def_id), Foreign(foreign_def_id)) => def_id == foreign_def_id.0,
-                (&ty::Error(..), Error) => false,
-                _ => false,
-            };
-            if provides {
-                return true;
-            }
-        }
-        false
-    }
-
-    fn associated_ty_value(
-        &self,
-        associated_ty_id: chalk_solve::rust_ir::AssociatedTyValueId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::AssociatedTyValue<RustInterner<'tcx>>> {
-        let def_id = associated_ty_id.0;
-        let assoc_item = self.interner.tcx.associated_item(def_id);
-        let impl_id = assoc_item.container_id(self.interner.tcx);
-        match assoc_item.kind {
-            AssocKind::Type => {}
-            _ => unimplemented!("Not possible??"),
-        }
-
-        let trait_item_id = assoc_item.trait_item_def_id.expect("assoc_ty with no trait version");
-        let bound_vars = bound_vars_for_item(self.interner.tcx, def_id);
-        let binders = binders_for(self.interner, bound_vars);
-        let ty = self
-            .interner
-            .tcx
-            .type_of(def_id)
-            .subst(self.interner.tcx, bound_vars)
-            .lower_into(self.interner);
-
-        Arc::new(chalk_solve::rust_ir::AssociatedTyValue {
-            impl_id: chalk_ir::ImplId(impl_id),
-            associated_ty_id: chalk_ir::AssocTypeId(trait_item_id),
-            value: chalk_ir::Binders::new(
-                binders,
-                chalk_solve::rust_ir::AssociatedTyValueBound { ty },
-            ),
-        })
-    }
-
-    fn custom_clauses(&self) -> Vec<chalk_ir::ProgramClause<RustInterner<'tcx>>> {
-        vec![]
-    }
-
-    fn local_impls_to_coherence_check(
-        &self,
-        _trait_id: chalk_ir::TraitId<RustInterner<'tcx>>,
-    ) -> Vec<chalk_ir::ImplId<RustInterner<'tcx>>> {
-        unimplemented!()
-    }
-
-    fn opaque_ty_data(
-        &self,
-        opaque_ty_id: chalk_ir::OpaqueTyId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::OpaqueTyDatum<RustInterner<'tcx>>> {
-        let bound_vars = ty::fold::shift_vars(
-            self.interner.tcx,
-            bound_vars_for_item(self.interner.tcx, opaque_ty_id.0),
-            1,
-        );
-        let where_clauses = self.where_clauses_for(opaque_ty_id.0, bound_vars);
-
-        let identity_substs = InternalSubsts::identity_for_item(self.interner.tcx, opaque_ty_id.0);
-
-        let explicit_item_bounds = self.interner.tcx.explicit_item_bounds(opaque_ty_id.0);
-        let bounds =
-            explicit_item_bounds
-                .subst_iter_copied(self.interner.tcx, &bound_vars)
-                .map(|(bound, _)| {
-                    bound.fold_with(&mut ReplaceOpaqueTyFolder {
-                        tcx: self.interner.tcx,
-                        opaque_ty_id,
-                        identity_substs,
-                        binder_index: ty::INNERMOST,
-                    })
-                })
-                .filter_map(|bound| {
-                    LowerInto::<
-                    Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>>
-                >::lower_into(bound, self.interner)
-                })
-                .collect();
-
-        // Binder for the bound variable representing the concrete impl Trait type.
-        let existential_binder = chalk_ir::VariableKinds::from1(
-            self.interner,
-            chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General),
-        );
-
-        let value = chalk_solve::rust_ir::OpaqueTyDatumBound {
-            bounds: chalk_ir::Binders::new(existential_binder.clone(), bounds),
-            where_clauses: chalk_ir::Binders::new(existential_binder, where_clauses),
-        };
-
-        let binders = binders_for(self.interner, bound_vars);
-        Arc::new(chalk_solve::rust_ir::OpaqueTyDatum {
-            opaque_ty_id,
-            bound: chalk_ir::Binders::new(binders, value),
-        })
-    }
-
-    fn program_clauses_for_env(
-        &self,
-        environment: &chalk_ir::Environment<RustInterner<'tcx>>,
-    ) -> chalk_ir::ProgramClauses<RustInterner<'tcx>> {
-        chalk_solve::program_clauses_for_env(self, environment)
-    }
-
-    fn well_known_trait_id(
-        &self,
-        well_known_trait: chalk_solve::rust_ir::WellKnownTrait,
-    ) -> Option<chalk_ir::TraitId<RustInterner<'tcx>>> {
-        use chalk_solve::rust_ir::WellKnownTrait::*;
-        let lang_items = self.interner.tcx.lang_items();
-        let def_id = match well_known_trait {
-            Sized => lang_items.sized_trait(),
-            Copy => lang_items.copy_trait(),
-            Clone => lang_items.clone_trait(),
-            Drop => lang_items.drop_trait(),
-            Fn => lang_items.fn_trait(),
-            FnMut => lang_items.fn_mut_trait(),
-            FnOnce => lang_items.fn_once_trait(),
-            Generator => lang_items.gen_trait(),
-            Unsize => lang_items.unsize_trait(),
-            Unpin => lang_items.unpin_trait(),
-            CoerceUnsized => lang_items.coerce_unsized_trait(),
-            DiscriminantKind => lang_items.discriminant_kind_trait(),
-            DispatchFromDyn => lang_items.dispatch_from_dyn_trait(),
-            Tuple => lang_items.tuple_trait(),
-        };
-        def_id.map(chalk_ir::TraitId)
-    }
-
-    fn is_object_safe(&self, trait_id: chalk_ir::TraitId<RustInterner<'tcx>>) -> bool {
-        self.interner.tcx.check_is_object_safe(trait_id.0)
-    }
-
-    fn hidden_opaque_type(
-        &self,
-        _id: chalk_ir::OpaqueTyId<RustInterner<'tcx>>,
-    ) -> chalk_ir::Ty<RustInterner<'tcx>> {
-        // FIXME(chalk): actually get hidden ty
-        self.interner.tcx.types.unit.lower_into(self.interner)
-    }
-
-    fn closure_kind(
-        &self,
-        _closure_id: chalk_ir::ClosureId<RustInterner<'tcx>>,
-        substs: &chalk_ir::Substitution<RustInterner<'tcx>>,
-    ) -> chalk_solve::rust_ir::ClosureKind {
-        let kind = &substs.as_slice(self.interner)[substs.len(self.interner) - 3];
-        match kind.assert_ty_ref(self.interner).kind(self.interner) {
-            chalk_ir::TyKind::Scalar(chalk_ir::Scalar::Int(int_ty)) => match int_ty {
-                chalk_ir::IntTy::I8 => chalk_solve::rust_ir::ClosureKind::Fn,
-                chalk_ir::IntTy::I16 => chalk_solve::rust_ir::ClosureKind::FnMut,
-                chalk_ir::IntTy::I32 => chalk_solve::rust_ir::ClosureKind::FnOnce,
-                _ => bug!("bad closure kind"),
-            },
-            _ => bug!("bad closure kind"),
-        }
-    }
-
-    fn closure_inputs_and_output(
-        &self,
-        _closure_id: chalk_ir::ClosureId<RustInterner<'tcx>>,
-        substs: &chalk_ir::Substitution<RustInterner<'tcx>>,
-    ) -> chalk_ir::Binders<chalk_solve::rust_ir::FnDefInputsAndOutputDatum<RustInterner<'tcx>>>
-    {
-        let sig = &substs.as_slice(self.interner)[substs.len(self.interner) - 2];
-        match sig.assert_ty_ref(self.interner).kind(self.interner) {
-            chalk_ir::TyKind::Function(f) => {
-                let substitution = f.substitution.0.as_slice(self.interner);
-                let return_type = substitution.last().unwrap().assert_ty_ref(self.interner).clone();
-                // Closure arguments are tupled
-                let argument_tuple = substitution[0].assert_ty_ref(self.interner);
-                let argument_types = match argument_tuple.kind(self.interner) {
-                    chalk_ir::TyKind::Tuple(_len, substitution) => substitution
-                        .iter(self.interner)
-                        .map(|arg| arg.assert_ty_ref(self.interner))
-                        .cloned()
-                        .collect(),
-                    _ => bug!("Expecting closure FnSig args to be tupled."),
-                };
-
-                chalk_ir::Binders::new(
-                    chalk_ir::VariableKinds::from_iter(
-                        self.interner,
-                        (0..f.num_binders).map(|_| chalk_ir::VariableKind::Lifetime),
-                    ),
-                    chalk_solve::rust_ir::FnDefInputsAndOutputDatum { argument_types, return_type },
-                )
-            }
-            _ => panic!("Invalid sig."),
-        }
-    }
-
-    fn closure_upvars(
-        &self,
-        _closure_id: chalk_ir::ClosureId<RustInterner<'tcx>>,
-        substs: &chalk_ir::Substitution<RustInterner<'tcx>>,
-    ) -> chalk_ir::Binders<chalk_ir::Ty<RustInterner<'tcx>>> {
-        let inputs_and_output = self.closure_inputs_and_output(_closure_id, substs);
-        let tuple = substs.as_slice(self.interner).last().unwrap().assert_ty_ref(self.interner);
-        inputs_and_output.map_ref(|_| tuple.clone())
-    }
-
-    fn closure_fn_substitution(
-        &self,
-        _closure_id: chalk_ir::ClosureId<RustInterner<'tcx>>,
-        substs: &chalk_ir::Substitution<RustInterner<'tcx>>,
-    ) -> chalk_ir::Substitution<RustInterner<'tcx>> {
-        let substitution = &substs.as_slice(self.interner)[0..substs.len(self.interner) - 3];
-        chalk_ir::Substitution::from_iter(self.interner, substitution)
-    }
-
-    fn generator_datum(
-        &self,
-        _generator_id: chalk_ir::GeneratorId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::GeneratorDatum<RustInterner<'tcx>>> {
-        unimplemented!()
-    }
-
-    fn generator_witness_datum(
-        &self,
-        _generator_id: chalk_ir::GeneratorId<RustInterner<'tcx>>,
-    ) -> Arc<chalk_solve::rust_ir::GeneratorWitnessDatum<RustInterner<'tcx>>> {
-        unimplemented!()
-    }
-
-    fn unification_database(&self) -> &dyn chalk_ir::UnificationDatabase<RustInterner<'tcx>> {
-        self
-    }
-
-    fn discriminant_type(
-        &self,
-        _: chalk_ir::Ty<RustInterner<'tcx>>,
-    ) -> chalk_ir::Ty<RustInterner<'tcx>> {
-        unimplemented!()
-    }
-}
-
-impl<'tcx> chalk_ir::UnificationDatabase<RustInterner<'tcx>> for RustIrDatabase<'tcx> {
-    fn fn_def_variance(
-        &self,
-        def_id: chalk_ir::FnDefId<RustInterner<'tcx>>,
-    ) -> chalk_ir::Variances<RustInterner<'tcx>> {
-        let variances = self.interner.tcx.variances_of(def_id.0);
-        chalk_ir::Variances::from_iter(
-            self.interner,
-            variances.iter().map(|v| v.lower_into(self.interner)),
-        )
-    }
-
-    fn adt_variance(
-        &self,
-        adt_id: chalk_ir::AdtId<RustInterner<'tcx>>,
-    ) -> chalk_ir::Variances<RustInterner<'tcx>> {
-        let variances = self.interner.tcx.variances_of(adt_id.0.did());
-        chalk_ir::Variances::from_iter(
-            self.interner,
-            variances.iter().map(|v| v.lower_into(self.interner)),
-        )
-    }
-}
-
-/// Creates an `InternalSubsts` that maps each generic parameter to a higher-ranked
-/// var bound at index `0`. For types, we use a `BoundVar` index equal to
-/// the type parameter index. For regions, we use the `BoundRegionKind::BrNamed`
-/// variant (which has a `DefId`).
-fn bound_vars_for_item(tcx: TyCtxt<'_>, def_id: DefId) -> SubstsRef<'_> {
-    InternalSubsts::for_item(tcx, def_id, |param, substs| match param.kind {
-        ty::GenericParamDefKind::Type { .. } => tcx
-            .mk_bound(
-                ty::INNERMOST,
-                ty::BoundTy {
-                    var: ty::BoundVar::from(param.index),
-                    kind: ty::BoundTyKind::Param(param.def_id, param.name),
-                },
-            )
-            .into(),
-
-        ty::GenericParamDefKind::Lifetime => {
-            let br = ty::BoundRegion {
-                var: ty::BoundVar::from_usize(substs.len()),
-                kind: ty::BrAnon(None),
-            };
-            tcx.mk_re_late_bound(ty::INNERMOST, br).into()
-        }
-
-        ty::GenericParamDefKind::Const { .. } => tcx
-            .mk_const(
-                ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from(param.index)),
-                tcx.type_of(param.def_id).subst_identity(),
-            )
-            .into(),
-    })
-}
-
-fn binders_for<'tcx>(
-    interner: RustInterner<'tcx>,
-    bound_vars: SubstsRef<'tcx>,
-) -> chalk_ir::VariableKinds<RustInterner<'tcx>> {
-    chalk_ir::VariableKinds::from_iter(
-        interner,
-        bound_vars.iter().map(|arg| match arg.unpack() {
-            ty::subst::GenericArgKind::Lifetime(_re) => chalk_ir::VariableKind::Lifetime,
-            ty::subst::GenericArgKind::Type(_ty) => {
-                chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General)
-            }
-            ty::subst::GenericArgKind::Const(c) => {
-                chalk_ir::VariableKind::Const(c.ty().lower_into(interner))
-            }
-        }),
-    )
-}
-
-struct ReplaceOpaqueTyFolder<'tcx> {
-    tcx: TyCtxt<'tcx>,
-    opaque_ty_id: chalk_ir::OpaqueTyId<RustInterner<'tcx>>,
-    identity_substs: SubstsRef<'tcx>,
-    binder_index: ty::DebruijnIndex,
-}
-
-impl<'tcx> ty::TypeFolder<TyCtxt<'tcx>> for ReplaceOpaqueTyFolder<'tcx> {
-    fn interner(&self) -> TyCtxt<'tcx> {
-        self.tcx
-    }
-
-    fn fold_binder<T: TypeFoldable<TyCtxt<'tcx>>>(
-        &mut self,
-        t: ty::Binder<'tcx, T>,
-    ) -> ty::Binder<'tcx, T> {
-        self.binder_index.shift_in(1);
-        let t = t.super_fold_with(self);
-        self.binder_index.shift_out(1);
-        t
-    }
-
-    fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
-        if let ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) = *ty.kind() {
-            if def_id == self.opaque_ty_id.0 && substs == self.identity_substs {
-                return self
-                    .tcx
-                    .mk_bound(self.binder_index, ty::BoundTy::from(ty::BoundVar::from_u32(0)));
-            }
-        }
-        ty
-    }
-}